The ASA Committee on Environmental Health is pleased to announce the release of the third edition of Greening the Operating Room and Perioperative Arena: Environmental Sustainability in Anesthesia Practice ( This resource document is widely read and referenced by clinicians, administrators, and policymakers across the globe. The field of health care sustainability has changed greatly since the second edition in 2017 (and the first edition in 2010.) The COVID-19 pandemic has raised awareness about the need for resilient supply chain solutions, such as reusable PPE and medical devices and the need to be better resource stewards (ASA Monitor 2020;84:28-9; Front Public Health 2020;8:590275). The Russian war on Ukraine has shed light on the precariousness of reliance on fossil fuels, propelling development of cleaner, energy-independent solutions ( In 2023 alone, the United States experienced 18 billion-dollar weather and climate related disasters (not including induced health care costs) ( Not only is climate change threatening the ability of health care systems to deliver continuous quality care, health care contributes to pollution that harms the patients we serve and ecosystems we depend upon for health, against the mission to first, do no harm. We must seek ways to improve both environmental performance and continuous quality care.

What follows is an executive summary of the ASA’s Greening the Operating Room and Perioperative Arena: Environmental Sustainability in Anesthesia Practice (

1. Introduction

Pollution is presently responsible for 9 million, or every one in six, deaths each year, mostly due to air pollution (Lancet Planet Health 2022;6:e535-47). Climate change is already harming human health, through more frequent and severe storms and floods in some regions, droughts and wildfires in others, increasing food and water insecurity, political instability and forced migration, and vector-borne illnesses. Globally, health care is responsible for approximately 5% of total greenhouse gas emissions and similar fractions of toxic air pollution, as well as other environmental contaminants hazardous to human health and ecosystems (Lancet Planet Health 2020;4:e271-9; Environ Res Lett 2019;14:064004; Lancet 2021;398:1619-62; Lancet 2019;394:1836-78; Lancet 2021;397:129-70). As the health care sector adapts to a rapidly changing climate, it must also reduce its own environmental impact, identify barriers to change, and make recommendations to achieve sustainable, resilient health care systems (Annu Rev Public Health 2023;44:255-77) (See Figure).

Figure: Climate impacts on health and health care systems (Annu Rev Public Health 2023;44:255-77).

Figure: Climate impacts on health and health care systems (Annu Rev Public Health 2023;44:255-77).

Perioperative services are the most energy- and resource-intensive areas of the hospital environment, generating about 30% of solid waste and the majority of its carbon footprint (Lancet Planet Health 2017;1:e381-8; Anaesth Intensive Care 2010;38:538-44; Br J Anaesth 2020;125:680-92). Anesthesiologists are uniquely positioned to address health care-related pollution through clinical practice improvement, education, research, and administrative leadership in developing hospital initiatives and environmentally supportive policies and programs. (Anesth Analg 2012;114:921-3; Anaesthesia 2022;77:201-12). The ASA document is intended to offer guidance to anesthesiologists in these activities.

2. Environmental Emissions Reporting and Life Cycle Assessment

Key points

  • Life cycle assessment is an internationally standardized scientific method (ISO 14040 and 14044) of quantifying emissions from the material and energy inputs associated with products and processes.
  • While global warming potential (carbon dioxide equivalents, CO2e) is the most well-known type of emission studied and reported, several standard categories of environmental impacts are routinely evaluated.
  • Life cycle assessment is frequently coupled with life cycle costing to combine both environmental impact and organizational financial cost considerations to aid decision-making.

3. Anesthesia Equipment and Supplies

Key points

  • Equipment choices must take environmental considerations and supply chain resilience into account.
  • Life cycle emissions and costs associated with single-use disposable and reusable equipment tend to favor reusable equipment.
  • Reprocessing single-use disposable devices is strictly regulated by the Food and Drug Administration (FDA) to ensure patient safety and can potentially save costs and emissions compared to wasting devices after single use.
  • Procedure kits should be reformulated and streamlined to eliminate waste.
  • Care must be taken to avoid premature equipment upgrades that are both costly to organizations and environmentally harmful.
  • Purchasing agreements can be negotiated to include taking back old equipment for refurbishing and donation, repurposing of parts, or recycling by a third-party verified green vendor.

4. The Environmental Impact of Inhaled Anesthetics

Key points

  • Volatile anesthetics and nitrous oxide (N2O) are potent greenhouse gases. N2O also contributes to depletion of the ozone layer.
  • Desflurane is the inhaled anesthetic that is the most potent greenhouse gas, with a global warming potential (GWP100) of 2,540, followed by isoflurane (539), nitrous oxide (273), and sevoflurane (144). However, clinical doses must also be considered.
  • Because N2O has relatively low potency, higher concentrations (and therefore mass quantities) are required to achieve clinical effects compared with volatile anesthetics. In clinically equivalent doses, ranked climate impacts: desflurane > nitrous oxide > isoflurane > sevoflurane.
  • Life cycle greenhouse emissions from inhaled anesthetics are several orders of magnitude greater than for propofol.
  • Mitigation strategies include:
    • 1) Avoiding inhaled anesthetics and using intravenous and regional anesthesia when clinically appropriate.
    • 2) If inhaled anesthetics are used, desflurane and nitrous oxide should be avoided unless there are clear clinical indications.
    • 3) Minimizing fresh gas flows.
    • 4) Abandoning central nitrous oxide pipelines and substituting portable tanks that remain closed between uses.
  • Waste anesthesia gas capture and destruction technologies appear promising but require additional research to verify extraction efficiencies and overall emissions reduction benefits.

5. Fresh Gas Flow Management

Key points

  • Minimizing fresh gas flows is an essential strategy to limit inhaled anesthetic pollution.
  • Review the ASA Statement on the Use of Low Gas Flows for Sevoflurane (October 18, 2023).
  • Safe, effective low fresh gas flow management requires continuous monitoring of inspired oxygen and expired anesthetic concentrations.
  • The minimum fresh gas flow provides enough oxygen to match consumption plus any gases lost due to leaks in the circuit.
  • Strategies to maximize efficient delivery of anesthesia occur throughout an anesthetic:
    • During maintenance, minimize fresh gas flow.
    • During induction, use high vaporizer concentration settings and low fresh gas flows, and consider pausing/turning off fresh gas flows during intubation.
    • During emergence, turn off the vaporizer early, initially maintain low fresh gas flows, and manage emergence timing with changes in fresh gas flow.
  • Modern carbon dioxide absorbents are designed to support safe and cost-effective low fresh gas flow practices, including when using sevoflurane.
  • Clinical consideration of the time to change blood and brain concentrations of the anesthetic in fragile or unstable patients must be part of the assessment of when and how to use low flow management.
  • Reducing fresh gas flow should never take priority over maintaining safe and effective concentrations of oxygen and anesthetic in the patient.

6. Intravenous Pharmaceuticals

Key points

  • Pharmaceuticals and their metabolites are commonly detected in the environment (air, soil, and water), including in tap water.
  • Anesthesiologists should consider the harm to the environment when selecting medications.
  • Anesthesiologists should avoid unnecessary use of medications.
  • Anesthesiologists should avoid excess preparation of medications.
  • The US Pharmacopeia (USP) sets guidelines for storage and handling of drugs (The Pharmacopoeia of the United States of America. 2nd Ed, 1820). Whereas drugs opened and prepared by anesthesia practitioners must be disposed of within a matter of hours, those prepared under Level V laminar hoods may keep for days to months depending on refrigeration conditions.
  • Anesthesiologists should understand and comply with proper drug disposal methods to minimize associated environmental impacts.

7. Waste Disposal Management

Key points

  • Operating rooms are responsible for approximately 30% of total hospital solid waste.
  • Ongoing staff education is essential to improve proper waste disposal segregation.
  • Proper waste stream management reduces environmental and financial costs.
  • In nature, waste from one system is feedstock for another. The circular economy principles seek to eliminate waste and keep materials in use as long as possible at their highest function and guide sustainable practices.

8. Donations

Key points

  • The primary goal of any donation should be the benefit of the recipient. Using such a method to “green” an operating room is a distant second.
  • Careful consideration, understanding, and communication are necessary to match the right type of donated equipment and supplies to the right facilities and caregivers.

9. Perioperative and Operating Room Design and Management

Key points

  • Several organizations offer health care-specific green design guidance for hospital and operating room renovations, new construction, and operations.
  • Abandoning central supply systems for nitrous oxide and shifting supply to portable tanks is one of the largest opportunities for mitigating waste and direct release of facility emissions.
  • The setback of heating, ventilation, and air conditioning (HVAC) airflow change rates in operating rooms is one of the most cost-effective means of reducing energy consumption in a health care facility.

10. Sustainable Conferences and Meetings

Key points

  • Minimizing the environmental impact of meetings can serve to raise attendee awareness of pollution mitigation opportunities and encourage action.
  • The vast majority of medical conference emissions stem from air travel, which can generate between 235-733 kg of CO2e per person, more than the total annual per capita emissions in some countries.
  • Virtual gatherings save time and expense, reduce pollution, increase equity, and may potentially elevate the safety of anesthesia care globally through greater access to education.
  • In-person meetings provide vast opportunities for networking, forging personal and professional relationships that cannot be replaced through virtual attendance. Hybrid gatherings can provide the most flexible opportunities.

The committees that plan in-person ASA meetings are communicating regularly with the ASA Committee on Environmental Health as we incrementally work toward the goals outlined in this document.

For the complete resource document, including the Anesthesiology Sustainability Checklist, the Perioperative Sustainability Team Checklist, the Sustainable Event Checklist, and 135 references, please see the ASA’s Greening the Operating Room and Perioperative Arena: Environmental Sustainability in Anesthesia Practice (